Analgesia during Extracorporeal Shockwave Lithotripsy: Fentanyl Citrate versus Parecoxib Sodium

Shockwave-induced pain may become an important issue during extracorporeal shockwave lithotripsy (SWL), although the new generation of lithotriptors generally produces less pain than previous models. The aim of the study was to compare the analgesic effect of a cyclooxygenase-2-specific inhibitor (parecoxib sodium) with that of our standard method of analgesia (fentanyl citrate) in patients who needed pain relief when undergoing SWL.Fifty-eight patients who were undergoing SWL for renal calculi were randomized to receive intravenously either fentanyl citrate (group A, n = 30) or parecoxib sodium (group B, n = 28) when they felt that their pain during the session became intolerable. Lithotripsy was recommenced 10 minutes after administration of analgesia. The severity of pain before and after administration of the analgesic regimens was evaluated using a five-level verbal scale. The effectiveness of each drug was evaluated with respect to degree of pain relief and ensuing tolerance of the procedure to completion, as well as the need for supplementary analgesia (half the standard dose of fentanyl citrate).The patients in the two groups were comparable with regard to age, sex, body mass index, and stone size. There was no statistically significant difference in the maximum energy level achieved as well as in the total number of shock waves given in the two groups. Administration of fentanyl citrate resulted in alleviation of pain and completion of SWL in 27 patients (90%), whereas parecoxib sodium was effective in five patients (17.8%) (P < 0.01). The remaining 23 patients in group B received supplementary analgesia, and 22 completed the lithotripsy session.Parecoxib sodium was not as effective as fentanyl citrate in alleviating pain during SWL. Its use, however, may lower the dose of opioid-based analgesia in this group of patients.